Giro d'Italia timing explained?

[Giro_Fan]

Hello all,

I'm watching the Giro stage 15. I'm wondering about the timing gaps that are shown on the top of the screen. They show the "Front of the Race" (i.e., the leader(s)). Then chasers and the Peleton.

The riders are going up a steep hill and the leaders are 4:30 ahead of the Peleton. Everyone is riding at around 14 km/hour. After the leaders go over the top of the hill they almost immediately start riding around 40+ km/hour yet their time lead doesn't increase even though the riders behind them are still going around 15 km/hour. Why are the leaders times not increasing considering that they are riding around three times as fast as the riders behind them for at least 4.5 minutes.

 

[Dogtrousers]

Short answer: I don't know.

This is something that I have thought long and hard about. I've even asked it on here.

That time all I got was "the times are taken from the motorbikes" which doesn't help in the least.

My theory is that the time answers the question:if you have two groups, A (leading) and B (chasing) then if the finish line was exactly where B is now, how much would A have won by?

In other words how long ago was the leader at point where the chaser is now?

That would ensure that if the leader hits a downhill and speeds up, then time gained on that isn't factored in until the chasers have been down that hill too.

But it also means that if the leader had to have a wheel change that took a minute, then that minute wouldn't affect the lead time until the chasers get to the point of the wheel change.

 

[Giro_Fan]

Thanks for your reply. Your answer makes sense but it is still a little confusing.

Thanks

 

[Specialeyes]

That's exactly it - pick a lamppost or piece of road fan art or indeed a KoM point and time how long between the breakway passing that point and the chasers then the peloton. That rolling gap is what's being measured.

When the peloton rolls over the top of the climb they'll accelerate to the same speed as the leaders did at the same point, so speed isn't what's being measured.

 

[figbat]

The distance will increase but the time between the groups won’t, since the chasing groups will accelerate over the top too. When the leaders hit the climb the following pack will have closed the distance but still remained the same time behind.

 

[Dogtrousers]

So if we think of this scenario. Rider X is the sole remant of the breakaway. As he hits the foot of the final climb he has a 10 minute lead on the peloton (ie it's 10 minutes since he rode over the bit of fan art that the peloton is currently riding over).

All is looking good for X but as soon as he passes the fan dressed as a giant piece of cheese, he snaps. He's allergic to giant cheese! His nerve goes and he starts wobbling all over the road. He's grimacing, sweat is pouring off him. He keeps going ... but only just. The gaps still shows 10 minutes. It stays at 10 minutes as X struggles to turn the pedals. The cameras show the peloton bearing down on X. "Surely the gap must be coming down" we say. But no, it stays at 10 until the peloton passes the fan dressed as a piece of cheese, whereupon it plummets.

 

[Regular.Cyclist]

There are several ways it is done which this website explains.

https://velo.outsideonline.com/news...t=The way a time gap,tool to measure the gaps.

 

[mjr]

It is worth remembering that the Giro's time estimates have long been less reliable than the two ASO grand tours. Not that ASO's timers are always right. Believe the helicopter shots more than the graphics.